The content of protein, fat, carbohydrates (mono- and disaccharides, starch), dietary fibre, ash, potassium, vitamin B1, B2, B6, C and carotenoids of raw and cooked (boiled, stewed) pumpkin/winter squash varieties Hokkaido, Deutscher Landkürbis, Connecticut Field, Baby Bear, Sankt Martin and Muscade de Provence was determined. Hokkaido squash (raw) contained 1.69 ± 0.58 g protein, 0.48 ± 0.18 g fat, 13.6 ± 1.76 g available carbohydrates, 2.37 ± 0.25 g dietary fibres, 1.17 ± 0.24 g minerals, 0.49 ± 0.10 g potassium, 3.74 ± 1.65 mg total β-carotene, 30 ± 6 mg vitamin C, 34 ± 10 μg vitamin B1, 67 ± 42 μg vitamin B2 and 306 ± 56 μg vitamin B6 per 100 g edible part (flesh with and without peel). The nutrient content of Hokkaido was two to five times higher than that of the remaining squash and pumpkin varieties analysed. After cooking (boiling or stewing for 30 min at 100 °C) of squash and pumpkin, no loss of protein, fat, carbohydrates, dietary fibre and minerals has been found if cooking water was included. Otherwise, 10% to 35% of leaching losses have to be calculated. Retention of vitamins varied between 98% and 73%. Of vitamin B 1 and C 14% to 25% and 21% to 27% were lost. The losses found for vitamin B2 and B6 (2-10%) were much lower. If cooking water was not included for the preparation of dishes, the losses of water soluble vitamins would be 10% to 30% higher. 8% to 20% of total β-carotenes were destroyed. 9% to 13% of trans-β-carotene, furthermore, were isomerised to cis-β-carotene.